The purpose of this project is to model the effects of temporary changes in Medicaid physician fees, removal of preventive care copayment rates and Medicaid eligibility expansion in the Patient Protection and Affordable Care Act of 2010 (PPACA) on the use of US Preventive Services Task Force (USPSTF) recommended preventive care among Medicaid enrollees. PPACA appropriates federal dollars to fund increases in physician fees for the Medicaid program to Medicare rates for 2013 and 2014. After 2014, the federal incentive expires and it is up to states to determine if they will continue to fund the payment increase using state funds if Congress does not fund an extension. Traditionally, each state has set its own Medicaid reimbursement rates and has had wide discretion in eligibility rules and copayment structure. Federal Medicaid law does not define preventive services, include these services under a mandatory benefit category or track specific preventive services covered for adults by each Medicaid program. This has led to substantial geographic variation in Medicaid plan design and use of preventive services, with not all USPSTF services covered in all states and substantial differences in provider reimbursement and beneficiary cost sharing. This study will examine the effect of the previous increases in physician fees on the use of USPSTF recommended preventive care services and model the projected impact of additional utilization increases under PPACA. Similarly, we will estimate the effects of the elimination of this financial incentive after 2014. We will also estimate the cost of increases in the use of these preventive services, resulting from the increase in physician fees, the removal of copayments, and the eligibility expansion to parents and childless adults. To answer these questions, we will use data from the Medical Expenditure Panel Survey (MEPS) and the National Ambulatory Medical Care Survey (NAMCS). The project will answer an important research question that will be critical for the next step in health reform. When the federal subsidies for higher Medicaid reimbursement and program expansions expire in 2014, states will make choices about which elements to retain and which to discard. It will be critical that there be scientific evidence regarding the impact of the different policy options. Currently, that evidence is lacking. This study will provide guidance to states about the likely effect of different policy choices on the use of preventive care in low income populations.